Definify.com
Webster 1913 Edition
Sienna
Si-en′na
,Noun.
[It.
terra di Siena
, fr. Siena
in Italy.] (Chem.)
Clay that is colored red or brown by the oxides of iron or manganese, and used as a pigment. It is used either in the raw state or burnt.
Burnt sienna
, sienna made of a much redder color by the action of fire.
– Raw sienna
, sienna in its natural state, of a transparent yellowish brown color.